Axial flow compressor

ABSTRACT

A supersonic axial flow compressor is formed with an annular compartment downstream of the rotor. The compartment is provided with axially extending dividers or partitions which divide the compartment into sub-chambers. The walls of the partitions form curved surfaces which are inclined to the direction of flow from the rotor to induce a succession of shock waves for increasing the static pressure. A collector is axially positioned with respect to the compartment and shares with the compartment a common dividing wall within which are formed a plurality of inclined passages which receive the flow and direct it into the collector. The passages are inclined both to the radius and the axis to accommodate the high speed flow without generating shock waves, and are formed with throats which converge and diverge in the direction of flow.

United States Patent 11 1 Stalker 1 5] Nov. 5, i974 [52] U.S. Cl415/206, 415/209, 415/210 [51] Int. Cl. F01d 9/00, F03b 3/16 {58] Fieldof Search 415/181, 206, 209, 210,

[56] References Cited UNITED STATES PATENTS 2/1953 Wosika 415/2103,285,567 11/1966 Richardson.. 3.652.184 3/1972 Conrad 415/209 FOREIGNPATENTS OR APPLICATIONS 991,675 4/1902 France 415/209 PrimaryExaminer-Carlton R. Croylc Assistant Examiner-Louis J. CasarcgolaAttorney, Agent, or Firm-Biebel, French & Bugg [57] ABSTRACT Asupersonic axial flow compressor is formed with an annular compartmentdownstream of the rotor. The compartment is provided with axiallyextending dividers or partitions which divide the compartment intosub-chambers. The walls of the partitions form curved surfaces which areinclined to the direction of flow from the rotor to induce a successionof shock waves for increasing the static pressure. A collector isaxially positioned with respect to the compartment and shares with thecompartment a common dividing wall within which are formed a pluralityof inclined passages which receive the flow and direct it into thecollector. The passages are inclined both to the radius and the axis toaccommodate the high speed flow without generating shock waves, and areformed with throats which converge and diverge in the direction of flow.

7'Claims, 5 Drawing Figures PATENTEDNUV 5 m4 FIG-4 I FIG AXIAL FLOWCOMPRESSOR BACKGROUND OF THE INVENTION This invention relates to elasticfluid compressors and more particularly axial flow compressors in whichthe flow of fluid from the compressor rotor is supersonic. Supersonicaxial flow compressors can produce .high compression ratios but theyoften present problems in diffusing the flow to increase thestaticpressure, and problems in turning the flow to a desired direction.

SUMMARY OF THE INVENTION In the present invention, means are disclosedfor increasing the static pressure in an axial flow compressor by firstpassing the flow from the compressor blades along'a curved surface. Itis known that supersonic flow of about Mach 1.7 when turned by a 12wedge will have a shock wave that drops the Mach number down to about0.92. This invention utilizes curved surfaces to create successiveinclined shock waves for effectively increasing the static pressure, incombination with inclined inlets or passages leading from a compartmentdefined by curved walls, into a collector.

The fiow from the rotor of an axial flow compressor is directed mainlyin the peripheral direction. This flow is reduced in velocity by passingthe supersonic flow along curved surfaces which take the form of axiallyextending walls or dividers defining generally annular sub-compartments.A common wall separates the subcompartments from a collector, andpassages or collector inlets are formed in this wall to direct the flowinto the collector. The inlets are inclined both to the radius and tothe axis and direct the flow substantially along the surface of the wallin the collector.

It is an accordingly important object of this invention to provide anaxial flow compressor in which curved wall means are employed to reducethe velocity of the supersonic flow.

A furtherobject of this invention is the provision of an axial flowcompressor in which the output of the compressor is received within acompartment defined by a radial series. of axially extending curved wallmeans. and in which a collector receives the flow from the compartmentthrough inclined inlet passages.

Another important object of the invention is the provision of acollector compartment in an axial flow compressor which has at least oneaxially extending divider which is curved in the direction of fluidflow, to induce a series of shock waves. The divider also reduces theintensity and magnitude of turbulence which would otherwise arise fromthe fact that there are different fluid velocities in the portions oftheflow from different radial portions of the compressor blades.

These and other objects and advantages of the inven-' tion will beapparent from the following description, the accompanying drawings, andthe appended claims.

.BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 discloses a compressoraccording to this invention, in axial section;

FIG. 2 shows a fragmentary development of the rotor;

FIG. 3 is a plan view ofthe compressor of FIG. 1 with the case beingpartially broken away;

FIG. 4 is a section on line 4-4 in FIG. 3; and

FIG. 5 is an enlarged development of a fragment of I the collectorparticularly to show the passages leading into the collector.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the figures in thedrawings, a supersonic axial flow compressor constructed according tothe teachings of this invention is shown in'and as including a rotor 20.The rotor 20 has blades 22 mounted on a hub 24 which is, in turn,mounted on a shaft 26 and supported for rotation on bearings 28 in acase 29. Fluid enters at the entrance 30 and flows between the blades 22in the direction of the arrows 33 and into an annular compartment 34.

The compartment 34 is subdivided into generally concentricsub-compartments including an inner subcompartment 35, a middlesub-compartment 36,-and an outer sub-compartment 37, by a pair of wallmeans or divider 40 and 41 and an inside wall 42. The dividers 40 and 41are extended generally axially in the direction of the rotor 20 and fromthe sub-compartment which receive flow.from corresponding axial regionsof the blades 22. The divider surfaces together with the walls of thecase 29 present curved surfaces to the flow from the compressor blades22.

As seen in FIG. 2, the flow from the blades 22 has a large peripheralcomponent of velocity and a relatively smaller axial velocity component.Since the dividers 40 and 41 are curved in the direction of flow theyprecipitate a succession of inclined shock waves which reduce thesupersonic flow velocity. While a pair of dividers 40 and 41 isdisclosed forming three sub-compartments, it is within the scope of theinvention to use more or less said dividers or to employ a singlespirally formed divider to assure the benefits of this invention.

The fluid is extracted from the compartment 34 into a collector bypreferably inclined inlets 43 which are formed in the rear wall 44 ofthe compartment 34. The rear wall 44 is also the front wall of thecollector 50. The inlets 43, as shown in FIGS. 4 and 5, are inclinedboth at an angle to the radius and at an angle to the axis toaccommodate the high speed flow without generating shock waves. Theinlets 43 may extend entirely across the compartment 34 or may extendonly across one of the sub-compartments as shown by the inlets 43Aextending across the outermost compartment 37 in FIG. 4. The collector50 has one or more conduits leading out of the collector for thedischarge of flow therefrom.

The inlets 43 direct the flow from the compartment 34 substantiallyalong the wall 44 within the collector 50. The inlets thus definepassages which may be formed with throats as defined by the wall 44 andinwardly extending fingers 62 which converge somefluid velocitiesexisting in the portions of the flow from.

corresponding radial portions of the blades 22.

It is preferred that the slots defined in the inlets 43 be placed asclose together as 12 of are. As this may not be practical this spacingmay be greater. However, the spacing of the inlets leading to thecollector from the outer sub-compartments 37 may be greater in number,as shown by the inlets 43A of HO. 4.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention.

What is claimed is:

1. In an axial flow compressor having a bladed rotor, the improvementcomprising an annular compartment positioned in downstream relation tothe rotor and adapted to receive the flow from the compressor blades,said compartment being defined by a back wall and axial wall meansextending from said back wall toward the compressor blades dividing saidcompartment effectively into a plurality of radially spacedsubcompartments, a collector positioned, axially downstream from saidcompartment, said compartment back wall forming a partition between saidcompartment and said collector, and means in said back wall defining aplurality of angularaly spaced inlets leading from said compartment intosaid collector, said inlets being inclined to direct the flow from saidcompartment into the collector substantially along the surface of saidback wall.

2. The compressor of claim 1 in which said inlets are formed with wallswhich converge and then expand in the direction of flow to diffuse theflow and increase static pressure.

3. The compressor of claim 1 in which said inlets extend alongstraightlines in said back wall at an angle to a radius.

4. The compressor of claim 1 in which there are a plurality of saidaxially extending wall means arranged in concentric relation.

5. In an axial flow supersonic compressor the improvement comprising anannular compartment positioned to receive flow from the compressorblades and having a back wall means, means in said compartment defininga generally axially extending partition effectively dividing saidcompartment into radial inner and outer sub-compartments, saidpartitions curving arcuately in the direction of rotational flow fromsaid blades thereby'reducing the velocity of supersonic flow by thegeneration of shock waves along the surfaces thereof, a collectorpositioned in axial relation to said subcompartments and separatedtherefrom by said wall means, and a plurality of inlet passages formedin said wall means leading from said compartment into said collector,said passages receiving the flows from said compartment, and beinginclined at an angle to the axis so that the exit flow from saidcompartment is in the same rotational direction as the flow in saidsubcompartments.

6. The compressor of claim 5 inwhich there is provided a pair of saidparitions dividing said compartment into radially outer, middle, andinner subcompartments.

7. The compressor of claim 5 in which said inlets are formed withthroats which converge and then expand in the direction of fluid flow todiffuse the flow.

1. In an axial flow compressor having a bladed rotor, the improvementcomprising an annular compartment positioned in downstream relation tothe rotor and adapted to receive the flow from the compressor blades,said compartment being defined by a back wall and axial wall meansextending from said back wall toward the compressor blades dividing saidcompartment effectively into a plurality of radially spacedsubcompartments, a collector positioned, axially downstream from saidcompartment, said compartment back wall forming a partition between saidcompartment and said collector, and means in said back wall defining aplurality of angularaly spaced inlets leading from said compartment intosaid collector, said inlets being inclined to direct the flow from saidcompartment into the collector substantially along the surface of saidback wall.
 2. The compressor of claim 1 in which said inlets are formedwith walls which converge and then expand in the direction of flow todiffuse the flow and increase static pressure.
 3. The compressor ofclaim 1 in which said inlets extend along straight lines in said backwall at an angle to a radius.
 4. The compressor of claim 1 in whichthere are a plurality of said axially extending wall means arranged inconcentric relation.
 5. In an axial flow supersonic compressor theimprovement comprising an annular compartment positioned to receive flowfrom the compressor blades and having a back wall means, means in saidcompartment defining a generally axially extending partition effectivelydividing said compartment into radial inner and outer sub-compartments,said partitions curving arcuately in the direction of rotational flowfrom said blades thereby reducing the velocity of supersonic flow by thegeneration of shock waves along the surfaces thereof, a collectorpositioned in axial relation to said sub-compartments and separatedtherefrom by said wall means, and a plurality of inlet passages formedin said wall means leading from said compartment into said collector,said passages receiving the flows from said compartment, and beinginclined at an angle to the axis so that the exit flow from saidcompartment is in the same rotational direction as the flow in saidsub-compartments.
 6. The compressor of claim 5 in which there isprovided a pair of said paritions dividing said compartment intoradially outer, middle, and inner sub-compartments.
 7. The compressor ofclaim 5 in which said inlets are formed with throats which converge andthen expand in the direction of fluid flow to diffuse the flow.